Why we still don't use water to run our engines?

Scientists had already discovered that hydrogen can be extracted from water to power a car (the media said so). But due to technological and political reasons that could seriously disrupt the oil industry.

Water is one of the most powerful and affordable sources of energy for sure. But why we still don't use it instead of oil, daily?

Mar 3 2011:
Assuming this truly can be done:
It's cheaper for us and better for the environment = AMAZING
It's bad for oil industries, capitalism because the supply of water is so high, and bad for most economies = NEVER WILL HAPPEN IF GOVERNMENTS CAN AVOID IT

this is indeed very sad but the truth, although you should take into account not all countries have a good water supply and that we have messed up our oceans far more than enough.

Mar 3 2011:
"Assuming this truly can be done..." It can't! You can prove anything if you start with a false assumption.

Water is nothing more than hydrogen combined with oxygen. The two elements are held together by a chemical bond. It doesn't matter how you separate the two elements from each other, whether by electrolysis, photosynthesis, or any other means, the energy required to break the bond is greater than the energy generated when they combine again, which happens when you burn hydrogen in oxygen. It has nothing whatever to do with the big bad oil companies, capitalism, or anything else except basic Grade 6 physics and chemistry.

Anyway, burning hydrogen in vehicles would be a non-starter as it has a tendency to explode. Experimental cars that do run on hydrogen use fuel cell technology, which is a whole nother issue. But you still can't get something for nothing.

Mar 3 2011:
We do not expect every country to follow suit in order for US to start making economical decisions.
Whether or not a country has a "good water supply": I will presume there are 'people' in the countries you're referring to, and seeing as people NEED water, I'm guessing there is some kind of supply.
And, when comparing the availability of water to that of oil in my own geographic region: I know where a river is nearby, but not an oil well... so does this help me determine that I don't have a "good oil supply"? Or can that shit be pumped through veins across the Earth for thousands of miles, just like water?

It is so tempting to rationalize the irrational beliefs, the conspiracy theories by seeing propaganda everywhere.
You guys can just as well believe that God conspired against men, when he made the LAW of conservation of energy.
Yes, plants do it, so do solar panels, but you can only get (on average) less then 1kW/m² - since that is how much energy we get from the Sun. Did the bad corporations or governments did that?

Governments, EU are not preventing that, actually, they are promoting that, often to a fault, by using tax money to support inefficient (expensive) solar plants.

Mar 3 2011:
holy cow, that is embarrassing. seems you skipped high school altogether, i can only hope not because of the terrible war you had there.

splitting water to hydrogen and oxygen requires energy. when burning into water, you get that energy back. this can be good for energy *storage*. but obviously not good as an energy *source*.

and, alas, it is not even good as storage. hydrogen is problematic and expensive to store. we already have much better storage mechanisms, like artificial gasoline and batteries. unfortunately they are still to expensive to become widespread.

Mar 4 2011:
You are linking to an obscure ten-year-old experiment that was conducted on an extremely small scale and that has failed to produce any meaningful practical results in the decade since it was done.

This whole thread illustrates the staggering lack of practical scientific knowledge in whatever segment of the population that TED is representative of. We might just as well be debating how many angels can fit on the head of a pin. Not using water as a fuel has nothing even remotely to do with governments, energy companies, money, the environment, saving the planet, or the availability of water supplies. If you want to put the "blame" on anything, blame chemistry. Stupid covalent bonds!

1, it sill would not make hydrogen any more practical to store
2, it sill would not make water an energy source
3, it sill would not make this process a viable economic alternative to existing technologies

Mar 2 2011:
The energy required to separate hydrogen from oxygen by electrolysis of water is greater than the energy expended when the two combine together again. It is basic physics and has nothing to do with the oil industry or politics. What you are asking for is a perpetual motion machine!

Mar 8 2011:
Ok, maybe this topic needs a different approach. I suppose that even hardcore fans of oil/gas will agree that if an alternative is available to oil (wind/sun/geo/hydrogen/etc), that would be great and something to pursue. However, suppose for a moment that wind energy would be a viable solution, it is a bit difficult to have cars driving around with a windmill on their roof. Right? So we need some method to transfer the energy that we generated on one end (wind/sun/etc) to a mobile unit such as a car. Maybe hydrogen is one of them, although there might be better alternatives.

The electric car option (http://www.ted.com/talks/shai_agassi_on_electric_cars.html) could be the first step. Even though I have doubts about the batteries. But this is definitely a step away from oil. Even if the electricity that is currently generated is generated through gas/oil/coal, it is possible to use alternative sources.

For the hydrogen option; in the case of the electric car, storing hydrogen is no longer an issue as this can be safely done on the ground in a safe area. The electricity generated can be stored in batteries that are placed in cars. The energy can otherwise be used in households/industries. It is true of course that scale is an issue. But that should not stop us from working on alternatives.

But driving a car on plain water is a bit far fetched in my opinion...

Mar 3 2011:
There is so many ways that we can power engines that are both good for the environment and affordable but the truth of the mater is, our governments care more about money than anything...including our planet. They would rather have our planet die than help it survive just save money....it makes no sense to me either. They are all worried about how oil companies and nations would lose money. For example, the united states would never advocate with true commitment to oil free energy because they have so much oil that they hope to make money off when the rest of the world runs low on oil supply. So to answer the question, we dont use water(clean energy) because our governments prefer killing our planet to save money. Ironic? They would rather save money and use it when the planet is dead?

Mar 3 2011:
Basically because there is no developed industry for photochemical based energy while there is one for purely chemical based industry it is pretty much a means to secure the industry from rapid collapse. People say capitalism thrives on innovation but truth is that rapid innovation is also it's collapse.

Mar 3 2011:
water is not a source of energy. Hydrogen is.
There is no abundant hydrogen available on our planet, the only way to get sufficient amount of hydrogen would be to use electricity to break the H2O molecule to get hydrogen. From extracted hydrogen, as a result, you will receive less energy in return as to the amount that you spent in creating hydrogen. In sum, you end up loosing more energy (using electricity), than getting in return.